Consider The Evidence: Med/Peds Journal Roundup

July 18, 2007

Food for thought: Chocolate to lower BP?

Filed under: cardiovascular, hypertension, JAMA — medblog @ 9:34 am

JAMA 7/4/07 –  Maybe some wizard medicine applies to muggles as well… An article in JAMA by Taubert et al. tests the theory that flavonols found in dark chocolate may lower blood pressure

 The study population consisted of 44 otherwise healthy subjects with upper-range prehypertension or stage 1 hypertension. Patients with any other major medical problems including CVD, diabetes, hyperlipidemia, etc were excluded. Study design was an RCT with investigators blinded, but subjects not – because they couldnt disguise the white and the dark chocolate. Patients were also counseled to abstain from any other cocoa products during the study.  Participants were instructed to take one 5.6(white) or 6.3(dark)  gram piece of chocolate per day.

At 6 weeks – no statistical difference between groups.
12 weeks: dark chocolate group BP was down 2.4/1.3 mmHg from baseline.
At 18 weeks the BP difference in the dark chocolate group was – 2.9/1.9 mmHg.
The white chocolate group: no change.
    
Looks like we have a winner.

For the basic science portion of the study, researchers measured plasma S-nitrosoglutathione. Basically they postulate that this compound is an intermediary between nitric oxide stores and active NO in the endothelium. They also measured 8-isoprostane, a measure of oxidative stress. Levels of S-nitrosoglutathione were significantly increased only in the dark chocolate group. 8-isoprostane levels were unchanged with intervention in both groups. Investigators concluded that the effect of dark chocolate was more likley from stimulation of endothelial NO production rather than changes in redox equilibrium between thiol and nitrosothiols. Big words aside – it seemed to work… at least in a healthy, homogenous, untreated population with mild HTN – although I dont seem to have alot of those in my practice….

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September 10, 2006

Din-o-mite: Intensive Lipid Lowering in CHD

Filed under: cardiovascular, CHD, lancet — medblog @ 8:33 pm

Lancet 9/9 – In the latest set of reccomendations from the NCEP ATP, the panel reccomended that patients with CHD or risk equivalent have a goal LDL of 100mg/dL, with an option of less than 70mg/dL in high-risk patients. Several prior studies have shown that further reductions in LDL may decrese mortality, but further study is needed.

In the most recent issue of the Lancet, Deedwania et al. publish results of the TNT study on the outcomes of this new goal of intensive lipid lowering. The design was a double blind RCT involving 10,000 patients with over a median of 5 years. To fit the inclusion criteria, subjects had to be aged 35-75 with history of MI, revascularization, or angina with objective evidence of atherosclerotic disease. Subjects were randomized to recieve either 10mg or 80mg of atorvastatin.

Mean LDL levels were 99mg/dL in the low dose, and 72.6mg/dL in the high dose group. The outcome was a statistically significant decrease in risk for major cardiovascular events in the high dose group. With an absolute risk reduction of 3.5% which is 29% relative. The levels obtained were convenient because they closely reflected the new LDL goals. It seems as if this study does show data to support those reccomendations. The question remains as to whether the results can be generalized to CHD risk equivalents such as diabetes, because the study only included clinically evident coronary disease. (more…)

August 23, 2006

Even more uses for ACE-I’s

Filed under: cardiovascular, hypertension, lancet — medblog @ 7:14 am

Lancet 8/19 – Updated guidelines for Abdominal Aortic Aneurysm screening were put out by USPTF last year reccommending ultrasound in men aged 65-75 who have ever smoked, especially due to the mortality and lack of medical treatment options for the disease. Clearly endovascular pathology related to atheroma and smoking are somehow involved. with AAA.
Enter ACE-inhibitors, which seem to be showing evidence of vasoprotective effects through some modulation of the renin-angiotensin system – also thought to be involved somehow with vascular pathology.

Hackam et al. publish a retrospective observational study in the current Lancet, investigating the use of ACE-I’s in patients with AAA. They analyzed records of 15,000 patients hospitalised with a primary diagnosis of abdominal aortic aneurysm in Canada. The researchers found that patients receiving ACE inhibitors before admission were significantly less likely to present with aortic rupture.(Adjusted Odds Ratio: 0.83) They conclude that the beneficial effect of such drugs is independent from their antihypertensive properties, because use of other antihypertensive agents was not associated with a lower risk of AAA. Clearly the study comes with all of the shortcomings of a retrospective study, and although we cannot conclude a causal effect, RCTs are warranted.

August 15, 2006

ACE-Is: ACE in the hole for atherosclerosis

Filed under: Cardiology, cardiovascular, lancet — medblog @ 11:12 pm

Lancet 8/12 – ACE inhibitors initially hit the big time due to two clearly beneficial effects: reduction of ventricular remodeling in heart failure, and renal protection in diabetes with hypertension. These studies also suggested ACE-inhibitors have some overall cardiovascular benefit independent of BP lowering and correction of heart failure. Could ACE inhibitors join statins as a class of drugs with multiple vascular benefits beyond the main mechnism it has traditionally known for??

Effects of ACE-Is were studied in the landmark trials HOPE, EUROPA and most recently PEACE. Dagenais et al.published an article looking at these three trials for statistical evidence of benefit in patients with atherosclerosis. And they found it: overall in the three trials, patients without heart failure on ACE therapy had significant risk reductions in cardivascular mortality, acute MI, and stroke. Each effect had an absolute risk reduction around 1%. Small, but significant.

Statins + ACE-inhibitors = crazy delicious.

June 13, 2006

More on Fish Oil Flop

Filed under: cardiovascular — medblog @ 9:09 pm

JAMA 6/14 – In March, the BMJ published a review (astutely blogged upon here) on omega-3 fatty acids, that basically showed no advantage to taking the stuff. One of the big hopes penned on the compound was the possibility of preventing some types of arrythmia.

Brower et al further crush this hope in an article in this weeks JAMA with the SOFA trial (seriously called that). They show that there is little to no anti-arrythmic effect of omega-3 supplementation on ICD patients. The study was an RCT done across Europe with over 500 patients over the period of a year.

Now, to wait for "that guy" who will write the editor saying the dose was too low, or the study period too short. Give it up buddy….

March 25, 2006

Omega-3 fatty acids: Just a fish tale?

Filed under: BMJ, cardiovascular — medblog @ 10:10 pm

BMJ – A meta-analysis published online first on BMJ.com casts doubt on the purported health benefits of omega-3 fatty acid supplementation. The new study contradicts a 2002 meta-analysis by Bucher et al. which found that intake these fatty acids were protective against fatal coronary events. The inclusion of data from a large European study by Burr in 2003 was the main influence for the new conclusion. From the figure of the source data, it appears that the largest RCTs such as GISSI-P actually favored less Omega-3. Some have even suggested that omega-3 FA's can be pro-arrythmogenic. The cohort trials appear to be clustered around the line of no benefit.

Clearly the trials included are highly variable on the type of intake (dietary vs supplemental) as well as the pre-intervention risk (from healthy to post-MI) – so although there may be a specific subgroup who would yield benefit, it appears that this analysis does not support a general reccomendation for increasing omega-3 fatty acid intake. Is something fishy going on? Hopefully futher research will find out…

February 23, 2006

bathtime fun and killing VRE, CRP for HTN?

Archives 2/13 – Why didnt anyone think of this earlier? Apparently a study by Vernon, et al. cleaning ICU patients with Chlorhexidine cloths effectively lowers patient colonization and contamination of healthcare workers’ hands and hospital surfaces. The intervention does a much better job than soap and water, or cloths alone. Anything to keep me from having to wear those stupid isolation gowns….

In another article – apparently you cant use CRP to measure risk all things cardiovascular. Unlike in older adults, CRP is not associated with risk of incident hypertension in young adults when adjusted for BMI – not suprising considering the two are probably strongly related…. (more…)

February 9, 2006

Lowfat = Low Yield for preventing CVD? WHI data

Filed under: cardiovascular, diet, JAMA, WHI — medblog @ 6:01 pm

JAMA 2/8 –  Not exactly a home run for the healthy low-fat diet. It is often taken for granted that lowering dietary is key to preventing CVD, and some suggest it may even prevent cancer. However, prospective data on the matter is scarce. This weeks JAMA presents the results of a large RCT on Low-fat diets as part of the Women’s Health Initiative – and the results are not exaclty helping me fight my McDonalds addiction.

(more…)

February 1, 2006

Connecting GFR to Cardiovascular Outcomes: ALLHAT

Filed under: annals of internal medicine, cardiovascular, hypertension, renal — medblog @ 2:45 am

Annals 2/7 – Picking apart two frequently co-morbid diagnoses, Rahman et al. propose that low GFR is an independent predictor for CVD in hypertensive patients. In fact, patients with a moderate to severe reduction in GFR had a higher 6-year incidence of developing CHD than ESRD.

They also report that amlodipne is less effective than the diuretic chlorthalidone in preventing CHD, and lisinopril is less effective than chlorthalidone in preventing heart failure. (more…)

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